1. Field of the Invention
This invention relates to products of manufacture which are substantially pure crystalline pterocarpan compounds which have been isolated from the crude extracts of natural products and to methods for isolating the compounds.
2. Description of the Prior Art
It has been known that the aqeuous alcoholic extract of the root of the South American cabeca de negra tree has been available to plantation workers in the upper Amazon jungle as an oral antidote against snake and spider venoms. About ten varieties of the species cabeca de negra are known in South America. Neither the nature of the active components nor studies on the side effects, pharmacological activity, stability and the like are known to have been published on the compounds of the invention. Pterocarpans possessing antimicrobial properties have been identified in the literature, see Heterocycles, Vol. 15, 1163 (1981).